Service and technical workers at UC San Diego Health are holding a one day strike Tuesday.
Workers say recently announced layoffs violate state law that requires such reductions to be negotiated, rather than enacted unilaterally.
Management has pointed to uncertain revenues and increased costs as reasons it was forced to lay off workers.
Both sides have been in contract negotiations for the past 16 months. Another strike is scheduled for Friday in San Francisco.
The work stoppage in San Diego is expected to last through midnight Tuesday.